The term protein-losing gastroenteropathy encompasses a wide group of diseases marked by the loss of protein through the gastrointestinal tract. The clinical presentation of these diseases can vary wildly but they share some aspects such as hypoalbuminemia, oedema, ascites, pleural and pericardial effusion and malnutrition. It is necessary to increase awareness of the significance of these clinical symptoms since they represent a serious complication which can significantly worsen the health of a patient and endanger their life. In addition to that, if these symptoms are observed, it is imperative that the full scope of different possible diseases is considered. Some of these diseases, such as Ménétrier’s and Whipple’s disease are rarer than others. Ménétrier’s disease is progressive and, same as Whipple’s disease, requires careful diagnostic testing so it can be adequately treated in time and all the possible serious complications can be avoided. Both diseases are inadequately researched because of their low prevalence in society. It would be ideal if the aetiology of Ménétrier’s disease was discovered, and the pathogenesis of both diseases was better understood so that treatment would be more effective without the need for radical intervention like gastrectomy in Ménétrier’s disease and with better knowledge of the effectiveness of different antibiotic options in Whipple’s disease. Additionally, clearing up the mechanism of protein loss through the gastrointestinal tract, which is still unknown in both diseases, could significantly improve the possibility of remedying the symptoms linked to hypoproteinaemia which can for now only be treated by curing the underlying disease.